border-1px($color)
    position relative
    &:after
        position absolute
        left 0
        bottom 0
        width 100%
        border-top 1px solid $color
        content ''
        transform-origin bottom left
        transform  scaleY(0.5)

border-none()
    &:after
        display none
        
bg-image($url)
    background-image: url($url + "@2x.png")
    @media(-webkit-min-device-pixel-ratio: 3), (min-device-pixel-ratio: 3)
        background-image: url($url + "@3x.png")

